Releasing spear for casing



May 29, 1962 DV A. SIRACUSA RELEASING SPEAR FOR CASING Filed May 31,1960 INVENTOR. DQNTEA-6//QQ aus@ ATTORN EY nited States Iid Patented May29, 1962 3,036,855 RELEASING SPEAR FOR CASING Dante A. Siracusa,Houston, Tex., assigner to Bowen Itco, Inc., Houston, Tex., acorporation of Texas Filed May 31, 196i), Ser. No. 33,033 7 Claims. (Cl.294-102) This invention relates to a releasing spear for casing and is`an improvement on my Patents No. 2,539,039 January 23, 195-1, and No.2,732,249 January 24, i956, both of which patents relate to an oil wellfishing spear. My present invention also relates to an oil well iishingtool whereby a lost section of pipe may be recovered from an oil well.The type of tool herein disclosed is commonly termed a spear in theindustry. If a lost section of pipe, termed the fish, cannot be removedfrom the well due to the fact that it is stuck tightly therein, then myspear can be readily released and withdrawn from engagement with thefish without injury to the tool. The tool is lowered into the oil welland the toothed members thereof, termed the slips, fit against theinside of the lost or broken pipe. These slips are -then expanded by thetool until they are indented in the wall of the pipe, and thereafterupon exerting an upward pull the lost pipe is loosened and brought tothe surface.

An object of my invention is to provide a novel resilient means at thelower end of the slips so that the slips will be frictionally heldagainst rotation, but will be permitted to move inwardly and outwardlywith relation to the mandrel of the tool by reason of their attachmentto a retainer, which is termed a unitizer.

Still another object of my invention is to provide a novel spring-likestructure which is coupled to lthe slip assembly in such a manner thatthe spring unit can move vertically into the lost pipe and frictionallyengage the same, and at the same time will hold the slips againstrotation relative to the lost pipe, except under a relatively highforce.

Other objects, advantages and features of invention may appear from theaccompanying drawing, the subjoined detailed description and theappended claims.

In the drawing:

FIGURE `l is a side elevation of my releasing spear for casing shown inposition in a pipe.

FIGURE 2 is a side elevation of my releasing spear with parts brokenaway to show interior construction.

FIGURE 3 is a fragmentary side elevation of the spring unit adjacent thelower end of the tool.

FIGURE 4 is a sectional view taken on line 4-4 of FIG. 3.

Referring more particularly to the drawing, this invention relatesprimarily to an improvement in the lower portion of the tool, that is,the means of frictionally holding the slip assembly against rotationrelative to the mandrel or body portion of the tool. The construction ofthe mandrel, the body of the tool, the slips, the method of hanging andsupporting the slips at their upper ends, and the method of supportingthe lower ends of the slips in a unitizer are all shown and described inmy prior Patents Nos. 2,539,039 and 2,732,249. Portions of the structurealready shown and described in my prior patents will again be described,at least in part.

My tishing spear for casings 1 comprises a coupling 2 which screws ontoor into a string of pipe upon which the tool is run. The coupling 2 issuitably threaded to receive this pipe. A mandrel 4 depends from thecoupling 2 and is threaded at its lower end to screw into a bottom nut5. This bottom nut 5 acts as a guide to direct the tool into the lost orstuck or broken section of pipe, which is termed the fish. The mandrel 4is a long tubular part which runs practically the entire length of thetool from the coupling 2 at the upper end to the nut 5 at the bottom.

The middle section of the mandrel 4 is formed with a plurality ofsuperimposed tapered seats 6 which are frustro-conical in shape. Thepurpose of these seats is to cam the slips outwardly, as will be furtherdescribed. Each of the seats 6 is formed with a horizontal shoulder '7at its lower end. A plurality of slips 3 surround the mandrel 4 and reston the seat 6. Each slip is formed with a plurality of tapered camsurfaces 9 which rest against the tapered seats 6. Each of the camsurfaces 9 terminate in a shoulder l@ at their upper end and thisshoulder opposes the shoulder 7 on the seats 6. The slips S are `eachformed with external teeth or wickers, all of which is usual and wellknown in the art. The slips 8, when assembled, completely encircle themandrel 4 and particularly the area where the seats 6 are formed; thusproviding a cylindrical structure which, when expanded, will engage theinside of the fish or pipe 11 with a substantially full circleengagement.

The coupling 2 may be formed with a depending annular apron l2 and eachof the slips 8 are provided with an upwardly extending blade 13 whichproject under the apron l2. The blades i3 serve as guides or retainersfor the upper part of the slips 8 and prevent these slips from fallingoutwardly before the tool has been inserted in the lost pipe 11. Each ofthe slips 8 are provided with an L-shaped slot or bayonet slot i4 andthe vertical portion of this slot coincides with a vertical space 1Sbetween adjacent blades 13. A lug 16 on the mandrel 4 extends into eachor" the vertical grooves `l5 and may be moved into the bayonet slot i4on downward movement of the mandrel 4, and subsequent rotation of themandrel to the right while the slips 8 are being held stationary. Thus areleasable support is provided for the Slips 8 at their upper ends whichpermit those slips to be held in a raised position relative to themandrel 4, that is, with the shoulders '7 and l0 contacting each otherand, therefore, with the slips 8 held in a compressed or minimumdiameter position.

Adjacent the `lower end of the mandrel 4l- I provide a unitizer 17 whichsurrounds the lower ends of the slips 8 and holds the lower ends ofthese slips in position around the mandrel 4. This unitizer is ixedly-attached to each or" the slips by means of the L-shaped fingers i9which iit into correspondingly shaped slots 20 in the unitizer. Theiingers 19 can move inwardly or outwardly relative to the unitizer 17,so that the slips can expand or contract, but all of the slips: are heldagainst vertical movement relative to each other by their coupling meansto the unitizer 17, that is, the lingers i9. The unitizer i7 is alsoformed with a vertical slot 2l which extends upwardly from the lower endthereof, and this slot receives a key 2.2 on the mandrel 4. A step 23,in the slot 2l, receives the key 22 when the mandrel 4 is loweredrelative to the slips S, and when the lug le enters the bayonet slot 14.

So that the slips S may all move in unison, `and also for the purpose ofpermitting vertical movement of the mandrel 4 and also limited rotationthereof relative to the slips 8, I provide a spring cage 24 whichsurrounds the unitizer i7 and is keyed to the unitizer by means of thelug 25 which projects upwardly therefrom into a groove 26 on the outsideof the unitizer. The spring cage 24 may be formed as a plurality ofoutwardly bent spring ingers, or it may be formed from a sleeve ofspring metal which has been belled outwardly and which has then beenslotted to form longitudinal fingers, substantially as shown in FlG. 3.The spring cage 24 is of sufficient outward diameter to tightly engagethe lost casing or fish ll and will frictionally engage the inside ofthe casing, thus permitting vertical movement of the fishing tool withinthe casing against the friction of the spring cage. However, rotation ofthe cage 24 and also the unitizer 17, and therefore the slips 8, will beresisted with considerable force due to the spring finger constructionof the cage 24. The spring cage 24 is held in position surrounding thesleeve portion 27 of the unitizer, by means of a snap ring 28 which isseated in the sleeve Z7 and projects slightly to act as a stop orshoulder for the spring cage 24. The spring ring 28 is positionedsomewhat below the lower edge of the cage 24 to permit elongation ofthat cage, due to compression when the cage enters the pipe or casingl1.

In Operation My tool is lowered into the well with the slips 8 in theirraised position, that is, the lugs i6 are in the bayonet slots 14 andthe key 22 rests in the step 23. The nut 5 will direct the spear intothe open end of the pipe or casing 1i. The spring fingers of the cage 24will contact the inner wall of the fish and hold the unitizer 17, thespring cage 24 and the slips S stationary until the shoulders 7 engagethe shoulders 1G. On downward movement of the mandrel 4 the slips 8 willnow be pushed into the pipe or casing 11. The slips 8 are now in theiruppermost position relative to the mandrel 4 and are compressed theirmaximum amount, The mandrel 4 is now rotated to the left which releasesthe lugs 16 from the bayonet slot 14 and moves that lug into thevertical groove 15. Simultaneously the key 22 is moved off of the step23 and into the vertical slot 2l. The mandrel 4 can now be pulledupwardly relative to the slips 8, since the slips 8 are frictionallyheld against vertical movement by the spring cage 24. The cam seats 6will now cam the slips 8 outwardly to expand these slips into a tightfull circle engagement with the inside of the pipe 11.

If it is desired to release the fishing tool from the lost pipe or fish,the mandrel 4 is first moved downwardly, at which time the slips 8 arestill held stationary against any downward movement by the spring cage24. Downward movement of the mandrel 4 will move the cam surfaces 6downward until the shoulders 7 and 10 engage. At this point the slips 8will be in their maximum inward or compressed position and willdisengage the fish il. Rotation of the mandrel 4 to the right will againengage the lugs 16 with their matching slots i4 to hold the slips intheir compressed position, permitting removal of the fishing tool fromthe sh.

Having described my invention, I claim:

l. A releasing spear for casing comprising a coupling, a mandreldepending from the coupling, tapered seats on the mandrel, a pluralityof slips surrounding the mandrel, tapered cam surfaces on said slipsresting on the first named tapered seats, releasable means engaging theupper ends of each of the slips and releasably holding these slips inraised position relative to the mandrel, a unitizer slidably mounted onthe mandrel for limited vertical movement on the mandrel and positionedbelow the slips, a finger on each of the slips at the lower end thereof,means on the unitizer engaged by the fingers to attach the unitizer tothe slips, a spring cage surrounding the unitizer and projectingoutwardlybeyond the periphery of the unitizer, said cage including aplurality of spring fingers.

2. A releasing spear for casing comprising a coupling, a mandreldepending from the coupling, tapered seats on the mandrel, a pluralityof slips surrounding the mandrel, tapered cam surfaces on said slipsresting on the first named tapered seats, releasable means engaging theupper ends of each of the slips and releasably holding these slips inraised position relative to the mandrel, a unitizer slidably mounted onthe mandrel for limited vertical movement on the mandrel and positionedbelow the slips, a finger on each of the slips at the lower end thereof,means on the unitizer engaged by the fingers to attach the unitizer tothe slips, a spring cage surrounding the unitizer and projectingoutwardly beyond `the periphery of the unitizer, said cage including aplurality of spring lingers, and means nonrotatably coupling said springmeans to the unitizer.

3. A releasing spear for casing comprising a coupling, a mandreldepending from the coupling, tapered seats on the mandrel, a pluralityof slips surrounding the mandrel, tapered cam surfaces on said slipsresting on the first named tapered seats, releaseble means engaging theupper ends of each of the slips and releasably holding these slips inraised position relative to the mandrel, a unitizer slidably mounted onthe mandrel for limited vertical movement on the mandrel and positionedbelow 4the slips, a finger on each of the slips at the lower endthereof, means on the unitizer engaged by the fingers to attach theunitizer to the slips, and spring means mounted on the unitizer, saidspring means projecting outwardly beyond the periphery of the unitizer,a key on the mandrel adjacent the lower end thereof, said unitizerhaving a slot therein to receive said key in one position, and a step inthe unitizer adjacent the slot to receive the key in another position ofthe parts.

4. A releasing spear for casing comprising a coupling, a mandreldepending from the coupling, tapered seats on the mandrel, a pluralityof slips surrounding the mandrel, tapered cam surfaces on said slipsresting on the first named tapered seats, releasable means engaging theupper ends of each of the slips and releasably holding these slips inraised position relative to the mandrel, a unitizer slidably mounted onthe mandrel for limited vertical movement on the mandrel and positionedbelow the slips, a finger on each of the slips at the lower end thereof,means on `the unitizer engaged by the fingers to attach the unitizer tothe slips, and spring means mounted on the unitizer, said spring meansprojecting outwardly beyond the periphery of the unitizer, and meansnonrotatably coupling said spring means to the unitizer, a key on themandrel adjacent the lower end thereof, said unitizer having a slottherein to receive said key in one position, and a step in the unitizeradjacent the slot to receive the key in another position of the parts.

5. A releasing spear for casing comprising a coupling, -a mandreldepending from the coupling, tapered seats on the mandrel, a pluralityof slips surrounding the mandrel, tapered cam surfaces on said slipsresting on the first named tapered seats, releasable `means engaging theupper ends of each of the slips and releasably holding these slips inraised position relative to the mandrel, a unitizer slidably mounted onthe mandrel for limited vertical movement on the mandrel and positionedbelow the slips, a finger on each of the slips at the lower end thereof,means on the unitizer engaged by the fingers to attach the unitizer tothe slips, a spring cage surrounding the unitizer and projectingoutwardly beyond the periphery of the unitizer, said cage including aplurality of spring fingers, a key on the mandrel adjacent the lower endthereof', said unitizer having a slot therein to receive said key in oneposition, and a step in the unitizer adjacent the slot to receive thekey in another position of the parts.

6. A releasing spear for casing comprising a coupling, a mandreldepending from the coupling, tapered seats on the mandrel, a pluralityof slips surrounding the mandrel, tapered cam surfaces on said slipsresting on the first named tapered seats, releasable means engaging theupper ends of each of the slips and releasably holding these slips inraised position relative to the mandrel, a unitizer slidably mounted onthe mandrel for limited vertical movement of the mandrel and positionedbelow the slips, a finger on each of the slips at the lower end thereof,means on the unitizer engaged by the fingers to attach the unitizer tothe slips, a spring cage surrounding the unitizer and projectingoutwardly beyond the periphery of the unitizer, said cage including aplurality of spring fingers, and means nonrotatably coupling said springmeans to the unitizer, a key on the mandrel adjacent the lower endthereof, said unitizer having a slot therein to receive said key in oneposition, and a step in the unitizer adjacent the slot to receive thekey in another position of the parts.

7. A releasing spear for casing comprising a coupling, a mandreldepending from the coupling, tapered seats on the mandrel, a pluralityof slips surrounding the mandrel, tapered cam surfaces on -said slipsresting on the first named tapered seats, lreleasable means engaging theupper ends of each of the slips and -releasably holding these slips inraised position relative to the mandrel, a unitizer slidably mounted onthe mandrel for limited vertical movement on the mandrel and positionedbelow the slips, 'a linger on each of the slips at the lower endthereof, means on the unitizer engaged by the fingers to attach theunitizer Ito the slips, and spring means mounted on the unitizer, saidspring means projecting outwardly beyond the periphery of the unitizer,and means nonrotatably coupling said spring means tothe unitizerconsisting of a lug projecting from the spring cage, -said unitizerhaving a groove therein to receive said lug.

References Cited in the tile of this patent UNITED STATES PATENTS

